Unlike credit cards, and HELOCs, loans are not revolving. The idea is you borrow a certain amount of money, and you pay off the money across a number of months until it is paid off. This is simple and to the point. As with revolving credit lines, the base interest is required to be displayed with information about the loan product. This could be an auto loan, mortgage, or personal loan. The issuer is not allowed to change the interest rate of the loan. This means there will never be an Adjustable Rate Mortgage (ARM).